The spine can be considered to be a series of joints made up of vertebrae and discs. Due to trauma, disease, and/or aging, the spine may be subject to degeneration. This degeneration may destabilize the spine and cause pain and/or nerve damage. Medical procedures are often required to either ease back pain, repair damage, or to prevent future damage.
One procedure that is often used to treat back pain or spinal damage is spinal fusion. Spinal fusion is a surgical technique used to combine two or more adjacent vertebrae. Supplemental bone tissue is used in conjunction with the patient's natural osteoblastic processes in a spinal fusion procedure. Spinal fusion is used primarily to eliminate back pain caused by the motion of the damaged vertebrae by immobilizing adjacent vertebrae. Conditions for which spinal fusion might be done include degenerative disc disease, treatment of a spinal tumor, a vertebral fracture, scoliosis, degeneration of the disc, spondylolisthesis, or any other condition that causes instability of the spine. One problem with a spinal fusion procedure is that, while the two fused vertebrae rarely detach from each other, the fusion procedure causes additional risk of damage to the adjacent vertebrae. Also, since the fused vertebrae can no longer move relative to one another, the spine can no longer provide the motion afforded by a healthy spine.
One alternative to spinal fusion is artificial disc replacement. Artificial disc replacement is a medical procedure in which degenerated or damaged discs in the spine are replaced with artificial ones. Like with a spinal fusion, an artificial disc replacement procedure is primarily used to treat back or neck pain, pain radiating into the extremities, and/or treat a spine damaged from degenerative disc disease. One goal of an artificial disc replacement is to eliminate back pain, while allowing normal spinal motion. One advantage over spinal fusion is that an artificial disc may prevent premature breakdown of adjacent vertebrae resulting from a spinal fusion procedure. One problem with artificial disc replacement procedures is that the artificial disc does not provide the same type of motion that a healthy disc does. Ideally, an artificial disc should allow the vertebral bodies to move relative to one another in a manner that provides an equivalent motion afforded by a healthy intervertebral disc, in such a way that the movement of the spine approximates the natural movement of a healthy spine. However, typical artificial discs allow some motion, but do not adequately approximate the natural movement of a healthy spine.
There is therefore a need for an artificial disc and related replacement procedure that adequately treats degenerative disc disease and other spinal conditions, while also enabling natural spinal articulations.